我们的星球（2019）

‎六万年前
Sixty thousand years ago
‎人类第一次走出非洲
humans left Africa for the first time.
‎此后 我们就不曾停下脚步
Since then, we haven't stopped
‎足迹遍布地球的各个角落
traveling to every corner of the Earth.
‎然而人类之旅只是众多旅程之一
But our journey is just one of many.
‎任一时刻
At any given moment
‎都有数十亿动物正在迁徙
billions of animals are on the move.
‎而我们星球的健康正有赖于此
And the health of our planet depends on it.
‎片名：我们的星球 2
‎迁徙是至关重要的生存策略
Migration is the most vital survival strategy.
‎不管是为了觅食…
Whether to feed...
‎为了繁衍
to breed...
‎还是为了找寻新家
...or to find a new home.
‎一路可谓不乏艰险
And it's not without risk.
‎本片沿途记录
This series traces extraordinary journeys
‎日新月异的世界中一段段非凡旅程
in a world that is changing faster than ever.
‎时至今日 我们才开始明白
And only now are we beginning to understand
‎地球上的一切生命
that all life on Earth
‎都有赖于迁移的自♥由♥
depends on the freedom to move.
（第一章 永不停息的世界）
‎‎双语合并：村儿南
‎博茨瓦纳的这片土地 ‎每年都在发生剧变
Every year, this land in Botswana is transformed.
‎就在三个月前 这里还有水体浸润
These scars are the only sign that it was covered by water
‎如今只剩这些疤痕为证
just three months ago.
‎彼时繁茂苍翠
Then, rich and green.
‎如今却荒枯贫瘠
Now, baked and barren.
‎这种改变促使动物们集体行动
This change drives animals to move en masse.
‎非洲水牛正在穿越喀拉哈里沙漠
Cape buffalo are marching across the Kalahari Desert
‎奔赴仅存的水源
towards the last remaining water.
‎小群聚而成大军
Groups have come together and formed a mega herd.
‎规模堪称非洲之最
The largest in Africa.
‎每一年 它们都进行同样的朝圣之旅
All are making the same annual pilgrimage
‎奔赴同一片偏远湿地
to one remote marsh.
‎而其它动物也指望着水牛的湿地之行
And others are relying on them to do so.
‎这些狮子是猎捕水牛的行家
These lions are buffalo specialists.
‎对狮群而言
And the mega herd's arrival
‎水牛大军的到来是一年中的头等要事
is the most important event of their year.
‎它们已经守候数周 ‎等待水牛大军的到来
For weeks, they've been waiting for the buffalo army.
‎一双双眼睛 ‎密切关注着地平线上的每一个身影
Eyes fixed on every shape crossing the horizon.
‎终于
Finally.
‎步步逼近的群落 ‎正如一面弯角和肌肉组成的墙
The approaching horde is a wall of horns and muscle.
‎但狮子必须找到其中的弱者
But the lions must find a weakness.
‎机会可能来了
And this could be it.
‎一头落单的公牛
A lone bull.
‎尽管他可能跟牛群走散了
He may be separate from the herd
‎但水牛的体重比狮子重四倍
but he is four times heavier than a lion
‎而且它还是非洲最凶猛的动物之一
and one of Africa's most dangerous animals.
‎狮群必须小心逼近
The pride must approach with care.
‎它们通常会漫不经心地 ‎一个接一个走向水牛
One by one, they casually walk towards him
‎仿佛对猎物不感兴趣
as if uninterested in a hunt.
‎事实上 他们是在排兵走阵
In fact, they're falling into position.
‎雌性轮流攻击…
The females take it in turns to attack...
‎消耗水牛的体力
tiring the bull.
‎此时 体重更胜一筹的雄性加入战斗
Now, the heavier males join the fight.
‎狮群的猎技已是炉火纯青
The pride has honed their technique so well
‎短短三分钟
that in just three minutes
‎它们就打败了凶猛的对手
they have defeated their most formidable opponent.
‎狮群赖以生存的这次迁徙
The migration on which the lions depend
‎只是数百万季节性迁徙的一个缩影
is one of millions driven by the seasons.
‎而反过来 这种种迁徙
And they, in turn
‎又是由另一段旅程促成
are a consequence of another journey.
‎地球绕日的周期之年
Our planet's year-long loop around the sun.
‎转动的过程中
As it travels
‎地球保持着23.5度的倾斜角
it does so on a tilt of 23 and a half degrees.
‎这种倾斜造就了不同的季节
And it is this that creates our seasons.
‎想要了解其中原理 ‎请将目光对准北极
To understand how, keep your eye on the North Pole.
‎这里每年有一半时间不受太阳照射
For half the year, it's angled away from the sun
‎全然被黑暗和寒冬笼罩
bringing darkness and winter.
‎其余的半年有阳光照射
For the other half, it swings towards the sun
‎日时较长
bringing longer days.
‎正是这样的年度周期
It's this annual cycle
‎推动了地球上规模最大的生物大迁移
that drives the greatest movements of life on Earth.
‎而在北半球 ‎它带来了一年中最大的变迁
And in the Northern Hemisphere, this brings the year's biggest change.
‎春天
Spring.
‎（三月）
‎三月下旬 ‎昼时延长的速度快过其他任何时节
In late March, the days lengthen faster than at any other time.
‎日照增加 土地迅速升温
Sunlight increases, quickly heating the land.
‎由此引发暴雨
Triggering rainstorms.
‎北半球骤然变暖
The Northern Hemisphere suddenly becomes warmer
‎也更加湿润
and wetter.
‎十分利于植物生长
Perfect for plants.
‎大地一片新绿
The land turns green.
‎一种动物以无敌之势 ‎尽享植物生长的繁荣
And one animal exploits the boom in plant growth like no other.
‎就在一周前
A week ago
‎这只埃塞俄比亚的沙漠蝗
this desert locust in Ethiopia
‎还只是一个怯生生和孤零零的小家伙 ‎而且几乎不怎么动地方
was a shy, solitary creature that moved very little.
‎现在可不然
Not anymore.
‎随着食物猛增
When available food skyrockets
‎蝗虫开启了集群模式
locusts switch to swarm mode.
‎它们开始行军
They start marching
‎并以十倍的速度繁殖
and multiply ten times faster.
‎随着蝗虫数目暴增
As their numbers explode
‎土地被啃得一片光秃
they strip the land bare.
‎所以为了寻找更多的食物
So to find more and more food
‎它们必须不断迁移
they must keep moving.
‎蝗群不断扩大
The swarm grows.
‎增长
And grows.
‎沿途植物被一扫而光
Devouring every plant in its path.
‎但这只是开始
But this is just the start.
‎陆路迁移的范围十分有限
On foot, they can only move so far.
‎若想去到更远的地方
To go further
‎就必须改换形式
they must change form.
‎蝗虫长出了翅膀
They grow wings.
‎如今 沙漠蝗胃口更盛
Now, with an even larger appetite
‎整支大军腾空而起
the entire army takes to the sky.
‎它们进食…
They eat...
‎飞行
and fly.
‎进食…
Eat...
‎飞行
and fly.
‎它们聚集一处 形成一只超级大军
They come together to form a super swarm
‎浩浩荡荡两千亿之众
200 billion strong.
‎这是70年来规模最大的蝗群
The biggest seen in 70 years.
‎它们每天消耗的食物
It consumes 400,000 tons of food
‎达40万吨♥
every single day.
‎所以若想全员果腹
So if the whole swarm is to feed
‎就必须迁移得更远更快
it must move further and faster.
‎蝗群日行100公里
It travels 100 kilometers a day
‎飞越农田与城镇
across farmland and towns.
‎席卷一个又一个国家…
It sweeps across country after country...
‎最令人震惊的是
and most astonishing of all
‎它们甚至横跨了红海
it even crosses the Red Sea.
‎（巴基斯坦）
‎这是首次有蝗群 ‎飞跃喜马拉雅山脉 到达西♥藏♥
It's the first time a swarm clears the Himalayas and reaches Tibet.
‎所到之处
Everywhere it goes
‎一片狼藉
it brings chaos.
‎蝗群不断迁移 ‎直至季节更替 带来干旱
It will keep moving until the changing seasons bring drought.
‎当食物最终消失…
For when their food finally disappears...
‎蝗虫也会消失
so will they.
‎（四月）
‎四月 北半球白昼持续变长
In April, day length in the North continues to rise.
‎日照增加 海洋变暖
The increase in sunlight warms the oceans
‎藻类生长繁盛
creating vast algal blooms
‎食源骤然丰富
and a sudden abundance of food.